<div class="play"></div>

<p>Hat-tip to <a href="https://github.com/CSS-Tricks/Shapes-Of-CSS">CSS Trick's <i>Shapes of CSS</i></a>.</p>

.play { 
  background: red;
  border-radius: 50% / 10%;
  color: #FFFFFF;
  font-size: 2em; /* change this to change size */
  height: 3em;
  margin: 20px auto;
  padding: 0;
  position: relative;
  text-align: center;
  text-indent: 0.1em;
  transition: all 150ms ease-out;
  width: 4em;
}

.play:hover {
  background: darkorange;
}

.play::before { 
  background: inherit;
  border-radius: 5% / 50%;
  bottom: 9%;
  content: "";
  left: -5%;
  position: absolute;
  right: -5%;
  top: 9%;
}

.play::after {
  border-style: solid;
  border-width: 1em 0 1em 1.732em;
  border-color: transparent transparent transparent rgba(255, 255, 255, 0.75);
  content: ' ';
  font-size: 0.75em;
  height: 0;
  margin: -1em 0 0 -0.75em;
  top: 50%;
  position: absolute;
  width: 0;
}

/* Other */

body, html {
  font: 100 1em/1.5 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

p {
  margin-top: 4em;
  text-align: center;
}